put a nelson pcm[mail order] in the truck in my signature.
I asked to reduce line pressure for my 1-2 shift as my built tranny chirped tires into 2nd gear at low rpm;s and shifted quite hard.
when i first drove the truck with the new pcm it shifted nice and smooth in the 1-2 but now it is getting back to where it was before.
also, i got the tune to try and get more timing than the stock radix tune was giving me, 12 deg at wot, got 16 deg with nelson pcm but was hoping for more.
the question is ... does the pcm really learn stuff and adjust itself based on
operating conditions over time, do you think that it will give me some more timing with learn time, it's been 2 weeks, i haven't checked the timing again
since the origional install.
what about the tranny, is there something that can be done to keep the setup that nelson did from being changed by the pcm, if in fact it is being changed.
truck runs like a dream by the way, noticable improvement with Nelson tune
and fuel economy improved as well

 

YES...the PCM DOES learn....the trans issue has to do with the shift-speed settings left at stock, set that way the trans will re-learn it's original settings....

 

cool. that's what i thought
I have ordered a afr gauge and will get Nelson to retune after I get some data from that.
But, do u think the pcm will improve timing in the meantime. what is a good # for timing with my setup?

 

I'm no tuning expert but I think that if Alan put 16* as the max then thats all youre gonna get. The PCM will pull timing due to knock but it wont add it just because there is no knock. I ran 20* on my 5.3 radix for awhile. But hey, that engine blew up. I run 17.5* max on my Tahoe now. 7psi.

 

Yes the pcm will learn, no it will not add timing-Unless in the ECT( engine coolant temp) or IAT table allen has them set up to add timing when the engine is cold or when the IAT's are VERY low. Basically once its up to temp it will not add any timing. I am not a expert but that is what I know.

 

trans and idle adaptive tables. read as adpative means the pcm will learn. just as yelo says, if you zero out the shift speed tables the vcm will shift as per the pressure tables and not try to learn.

Timing is as is. Other things might effect it though, if Allen says he gave you 16* and you see 14* then something is pulling 2*, beit IAT, ect, kr, burst knock, egr, , blah blah correction tables.

FWW, 16* is a common spark the tuners will give ya if you want more. It's a good safe number for a stock raidx setup. Get alky, larger hxr, or something to help battle your IATs and you can get more spark. Or..living in Novia Scotia , you could probably get away with 18* safely.

 

thanx again guys, I measured the timing with scanner
75 amb, 130 iat and 190 ect at the time.
so the tune will not have a max commanded timing but will adjust with temp conditions?
and 16 deg is not to bad anyway?